1) what is the difference between a measurement and an observation?
question options:
measurements are made with tools; observations are not.
observations are biased, while measurements are always unbiased.
measurements are compared to a standard; observations are not.
observations are only indirect ways of gathering data.
2) understanding how your heart works can best be done by which of the following?
question options:
measuring your pulse
making a model that simulates the heart’s functions
observing how you respond to exercise
hypothesizing about how the heart works

When many atoms are split in a chain reaction, a large explosion occurs. this is an example of what type of energy conservation

As part of an industrial process, air as an ideal gas at 10 bar, 400k expands at steady state through a valve to a pressure of 4 bar. the mass flow rate of air is 0.5 kg/s. the air then passes through a heat exchanger where it is cooled to a temperature of 295k with negligible change in pressure. the valve can be modeled as a throttling process, and kinetic and potential energy effects can be neglected. (a) for a control volume enclosing the valve and heat exchanger and enough of the local surroundings that the heat transfer occurs at the ambient temperature of 295 k, determine the rate of entropy production, in kw/k. (b) if the expansion valve were replaced by an adiabatic turbine operating isentropically, what would be the entropy production? compare the results of parts (a) and (b) and discuss.

Why does the equilibrium position of the spring change when a mass is added to the spring? will the mass oscillate around the new equilibrium position of the spring or the previous position without a mass attached to the spring? if the equilibrium position of the spring changes by 20 cm (assuming no initial mass) when a mass is added to the spring with constant 4.9 kg/s^2, what is the mass of the object attached to the spring?